Potential of herbal extracts to avoid the bacterial infection of Enterobacter cloacae in common carp, Cyprinus carpio L.

Abstract The study shows the possibility of herbal aqueous extracts to avoid the infection caused by Enterobacter cloacae in the common carp. The E. cloacae vaccinated on agar plates wherever placed to the filter discs, which were intended by filtration of the aqueous extracts (Six herbal species and four concentrations 10%, 15%, 20% and 25%) of Curcuma longa (Turmeric), Panax ginseng (Ginseng), Cinnamomum zeilanicum (Cinnamon), Thymus vulgaris (Thyme leaves), Olea europaea (Olive leaves), Eugenia caryophyllata (Clove). The herbal extracts inhibit the growth of E. cloacae in the highest concentrations (22 mm inhibition zone in 25%) with C. longa which appears to be the most efficient one, whereas the clove was the least efficient. The current study indicates that attainable and inexpensive herbal extracts may be efficient natural agents for preventing infection of E. cloacae in fish, and they also have been compared with some antibiotics. Furthermore, a study is required in order to carry out the herbal extracts and to detect the proper practice used in aquaculture.